Arkham Mansion--Part 2

Search Arkham Mansion to Find Dr. Young's Research Notes Before Joker

Inside, you'll spot three enemies just below. It's best to glide-kick the armed one to knock him down, then focus on the other two before he gets back up. Once clear, you'll find that the main door is locked--instead, grapple on top of the ventilation piped overhead, then use the Batclaw to rip off the ventilation grate just above before grappling inside.

There, use detective mode to spot a weak section of wall that can be detoated, revailing a Chronicle that can be scanned, as well as another vent that can be entered.

You'll drop onto a ledge overlooking numerous baddies below. This is the most amount of thugs you've fought yet, so make liberal use of your Stun Cape, giving you time to perform the ground-takedown when necessary. Once clear, head up the stairs, bust into the small office on the right via the vent for an Interview Tape, then proceed through the large door on the left, leading into the West Wing Corridor.

Take down the guard ahead to free the cops then continue through the far door into the Records room.

Two guards are being held hostage by a large group of baddies, all of whom are armed to the teeth. As such, stealth is going to be essential. Luckily, a single guard lurks on the raised walkway, to the left. Grapple up there and stealthily take him down. This will soon draw the attention of the others (thanks to the Joker's monitoring of the henchmen's vitals via their dog collars), so hightail it to a gargoyle to remain out of sight. Now you'll have to try and pick off the remaining enemies one-by-one, so that they don't open fire on you. The best way to do this is to use Detective Mode to easily keep an eye on everyone in the room, then swooping in on anyone who ventures out-of-sight of the rest of the group. For instance, if everyone but one drops to the lower level, target the single foe remaining on the walkway. The key is to be patient, and don't forget to use some of your advanced weaponry if you have it, such as the Remote Control Batarang or Auto Proximity Detonation, both of which are handy for stunning opponents from afar. Once you've cleared the room, proceed through the door on the northern side.